Question

In a conference there are $11$ mechanical engineers and $7$ metallurgical engineers. In how many ways can they be seated in a row such that all the metallurgical engineers sit together?

• A. $18!\times 2$
• B. $12!\times 7!$
• C. $11!\times 7!$
• D. $18!$

Answer 1

The correct option is B $12!\times 7!$

Take $7$ engineers as one entity.

So there are $12$ entities.

While engineers of metallurgical can arrange themselves in $7$! ways.

Total number of ways $=12!\times 7!$